I've only read a few of these novels ("Alas, Babylon", "The Towers Trilogy", "The Chrysalids", & "The Dispossessed"), but in this day & age of e-vangelicals making federal policy decisions, nuclear war no longer seems quite so fictional.

I have seen both filmed versions of "On The Beach" (I like both of them: the first because it's a film classic starring Ava Gardner, Fred Astaire, & Gregory Peck; the second --starring Armand Assante, Rachel Ward, & Bryan Brown-- because it's more detailed and graphic with a much more tragic young couple), and the silly but fun version of "Damnation Alley" starring George Peppard, Dominique Sanda, & Jan-Michael Vincent. There was a made-for-TV version of "Alas, Babylon" in 1960 featuring Dana Andrews & Rita Moreno, but I haven't found a copy available on tape or dvd yet. Of course there are "The Day After" starring Jason Robards & John Lithgow, and the British film "Threads", which is even more graphic. Not to mention the 50's classics "Five" and my all-time fav, "The World, The Flesh, & The Devil". But I don't think any of these began as science fiction novels such as these:

Whitley Strieber and James Kunetka's "Warday" (1984)

Helen Clarkson's "The Last Day: A Novel of the Day After Tomorrow" (1959)

Philip Wylie "Tomorrow!" (1954) & "Triumph" (1963),

Martin Caidin's "The Long Night" (1956)

Robert A. Heinlein's "Farnham's Freehold" (1964)

Merril's "Shadow on the Hearth"

Dean Ing's "Pulling Through" (1983)

Sven Holm's "Termush" (1967)

Mordecai Roshwald's "Level 7" (1959)

Philip K. Dick's "The Defenders" (1953)

Harlan Ellison's "A Boy and His Dog" (1969)

Ursula Le Guin's "Always Coming Home" (1985) & "The Dispossessed" (1975)

Poul Anderson and F. N. Waldrop's "Tomorrow's Children." (1947)

Clifford D. Simak's "There Will Come Soft Rains"

Nevil Shute's "On the Beach"

Pat Frank's "Alas, Babylon" (1959)

Jonathan Schell's "The Fate of the Earth" (1982)

Robert C. O'Brien's "Z for Zachariah" (1974)

James Sallis's "Jeremiad" (1969)

Suzy McKee Charnas's "Walk to the End of the World" (1974)

Virginia Fenwick's "America R.l.P." (1965)

David Graham's "Down to a Sunless Sea" (1979)

Paul 0. Williams's "The Dome in the Forest" (1976)

Vonda McIntyre's "Dreamsnake" (1978),

Philip K. Dick and Roger Zelazny's "Deus Irae" (1976),

Zelazny's "This Immortal" (1965) and "Damnation Alley" (1969) (also in "The Cursed Earth" [1982]

John Wyndham's "The Chrysalids" (1955)

Samuel R. Delany's "The Towers Trilogy" [1971]

Bruce Ariss's "Full Circle" (1963)

Jim Harmon's "The Place Where Chicago Was" (1962)

Poul Anderson's "Maurai" series

Russell Hoban's "Riddley Walker" (1980)

Walter M. Miller, Jr.'s "A Canticle for Leibowitz" (1955-57)